What did you work in if you don't mind me asking?
Edit: When I made the shift initially from dev to SDET, I had a 50% pay rise. In London I regularly get approached for £85k/$100k roles as an SDET. True devs might earn more than that at the same companies but it’s already much higher than most devs earn in the UK, and I’m not experienced enough to compete for the dev counterpart roles.